Hoist brake



Patented Oct. 10, 1950 UNITED STATES PATENT OFFICE 2,525,434 nors'r BRAKE William G. Wehr, East Cleveland, Ohio, assignor I to The Cleveland Crane & Engineering Company, Wickliffe, Ohio, a corporation of Ohio Application December 31, 1943, Serial No. 516,319

. 14 Claims.

The present invention relates to hoists and, more particularly, to hoist brakes of the' type which sustain theload automatically at any point and regulate the speed when lowering. Hoist brakes of this character are generally referred to as load brakes and are used extensively on overhead traveling cranes and the like.

The principal objectlof the present invention is the provision of a novel and improved load brake of the character referred to especially adapted for use on overhead traveling'cranes, which brake Will be simple in construction, aircooled, and reliable' and free 'frombhat'ter 'in operation. The matter of chatter isnot only more serious in the case of an overhead traveling crane than in other hoist devices but also more difficult to eliminate because of the" fact that the hoist mechanism is carried by a trolley movably supported on a bridge, which bridge is inherently resilient and; in turn, movably supported on the crane 'r'unwaysf Other objects of thejinvention are the provision of a novel and" improved air-cooled load brake of the character referred to which will have a large braking area located at a maximum distance from the center of rotation of the various parts while maintaining the overall diameter of the device at, a minimum; which will have the heat generating surfaces located adjacent to the outside of the device, thus facilitating rapid dissipation of heat generated thereby; wherein there is substantially no possibilitytof the-load being released by the failure of any part of 4 the device; and which is self-adjusting throughout the entire lifeof the braking sur face or surfaces.

The invention resides in certainconstructions' and combinations and arrangements of parts and further objectsand advantagesthereofwill be apparent to those skilled in theart to which the invention relates from the following description of the preferred embodiment descri-bedwith reference to the accompanying drawings in which similar reference characters. designate corresponding parts throughout the several views, and in which Fig. 1 is a plan 'view overhead traveling crane embodying the present invention; Fig. 2 is an elevational view of the. load brake shownin Figure 1, -with portions in section, approximately on the line 2-2 Fig.3;

Fig. 3 is a sectional view, with portions in elevation, approximately on the line 33, Fig. 2;

Fig. 4 is a sectional view approximately on the line 4- l', Fig. 2, and i of the hoist trolley of an V Fig. 5 is a perspective view shown in Figs. 2 and 3.

In view of the fact that the load brake of the present invention is particularly designed and adapted for use on overhead traveling cranes, it is herein shown as embodied in a hoist trolley of such a crane. Referring to the drawings, the reference character A designates a crane trolley adapted to be supported on a crane bridge and moved therealong by a reversible motor it. The bridge is, in turn, movably supported on crane runways comprising rails suitably fixed to the sides'of the building or structure within which the crane is located. The particular construction-of the crane trolley shown, aside from the load'brake hereinafter specificall referred to, forms no-part of the present invention.

The crane trolley A is provided with hoist of the thrust link mechanism, including a hoist or load cable l3,v

both ends of which are connected to a cable drum l4 rotatably supported in the trolley frame and operatively connected to a reversible electric hoist motor l5 also carried by the trolley. The load cable 13 is of conventional construction and is secured to the cable drum and to the trolley frame in the usual manner. As shown, the rotor of the hoist'motor i5 is provided with a pinion l6 continuously in mesh with a gear ll fixed to one end of a transversely extending shaft 13 rotatably supported in suitable bearings fixed to the trolley frame. The opposite end of the shaft I8 is connected to the load brake, designated generally by the reference character D, in a manner hereinafter described and carries a pinion 20 rotatably mounted thereon which is :also connected to the load brake. The pinion 26 is continuously in mesh with a gear 2! fixed to the'cable drum Id.

The right-hand end of the shaft l8, as viewed in Fig. 2, extends beyond the side member 23 of the trolley frame and the projecting end. thereof is rotatably supported by an anti-friction bearing 24 in an outboard support or bracket 25 bolted to the projecting end of a bracket 26 welded to the trolley frame. The end of the shaft i8 is of slightly reduced diameter and has a brake shoe assembly fixedly keyed thereto. As shown, the brake shoe assembly comprises a built-up carrier member E, including a plate or disk-like member 30 welded to the left hand end of a tubular member 3| and a somewhat similar disk or plate-like member 33 detachably secured to the disk or plate-like member 30 by bolts 3 and held in predetermined spaced relation with respect thereto by spacer members 35 surroundingy 1 6 bQltS 34. For facilitating assembly, the

3 spacer members 35 are welded to the plate or disk-like member 8 The disk-like members 38 and 33 extend transversely of the shaft l8 and the tubular member 3| and the member 35 are keyed to the shaft by a key 35, which key also keys a spacer member 31, hereinafter referred to, to the shaft l8.

In addition to the built-up carrier member E just described, the brake shoe assembly comprises a plurality of brake shoes 38, in the present instance two, pivotally supported at one end to the carrier member E for movement about axes offset from but parallelwith the axis of rotation of the shaft l8 by bolts 48 fixed in suitable aligned apertures in the plates 38 and '33. The circumference of the brake shoes 38 is cylindrical to conform with the cylindrical interior of a brake drum assembly, designated generally by the reference character F, including a member 4| The brake shoes 38 are provided with brake lining 42 which directly engages the brake drum. The brake lining 42 may be of any conventional construction and, among other things, insulates the brake shoes proper and the interior of the device against the heat produced incident to its engagement with the brake drum member. The interior cylindrical surface of the brake drum member F with which the brake shoes engage is coaxial with the axis of'rotation of the shaft l8 and the memberF is rotatably supported coaxial therewith by anti-friction bearings 43 and '44,

upon the right-hand end of the brake shoe carrier member E and a sleeve-like driven member 85 rotatably supported on the shaft l 8; The brake drum assembly F also includes a disklike member 58 detachably secured to the righthand end of the member '41 by screws 5| and through the medium of which the end of the member 4! is rotatably supported by the antifriction bearing 43.

The bearing 43 is, held in assembled position with respect to the brake drum assembly F by a plate '52 detachably secured to a hub-like part 53 of the member 58 by screws 54. As shown, the hub-like part 53 is made separate from the part 55 and welded thereto, however, it is to be understood that any suitable construction may be employed. Thebrake shoe assembly is maintained in position on the end of the shaft M3 by the spacer member 3?, previously referred to, interposed between adjoining ends of the member 3! andthe inner race for the anti-friction ably supported on the hub 63 of the member 4t and including a projecting arm 64 the end of which is connected to the pawl 58 radially inwardly of the pivot 60. by an S-shaped link 65 pivotally connected to the pawl 58 and the arm 164. The two parts of the friction ring 62 are resiliently held together by springs 18 and If surrounding bolts 12 and [3 connecting the parts together and interposed between the lower half as viewed in Fig. 5 and the nuts on the bolts. Movement of thepawl 58 away from the ratchet teeth 51 is limited by an adjustable stop in the form of a screw 14 threaded into a member 15 welded to the member 6!. The screw 14 is provided with a locknut 16 for retaining the former in any adjusted position. The construction is such that the pawl 58 allows rotation of the brake drum assembly F in one direction only, which direction is clockwise as viewed in Fig. 3. If desired, a spring-pressed or gravity-actuated pawl may be employed in place of the preferred construction shown; however, this alternative construction is subject 'to considerable wear "and is noisy in operation.

The sleeve-like member 45, previously referred to, and, in turn, the shaft l8 are rotatably supported by an anti-friction bearing 88 in a journal 8| bolted to the top of the frame member 23 as by bolts 82 and the left-hand end of said sleeve member 45, as viewed in Fig. 2, is operatively connected to the pinion '28 by interlocking teeth'83' and 84. The interlocking teeth 83and 84 which form the driving connection between the sleevelike member and the pinion 28 facilitate assembly of the various parts; however, it "is tobe understood that any suitable alternative constructions may be employed. The right-hand,

end of the sleeve-like member 45 which projects within the carrier member E is enlarged and provided with a plurality of elongated slots or apertures 85, in the present instance two, which slots or apertures are tangent to a circle inter- V mediate the inner and outer diameters of said bearing .24 and, in turn, the inner race of the anti-frictional bearing 29 isfixed to the end of the shaft is by a member held in position on the end of the shaft M3 by a bolt 56. Thespacer member 3! also retains the inner race of the bearing 83 in position on the end of the member 3!. The outer race of the anti-friction bearing 21; is fixed in the outboard support bracket 25. opposite sides of the various bearings are enclosed by suitable seals ofconventional construction with the exception of the right-handside of the bearing 28 which is closed by the outboard support or bracket 25.

The member ll of the brake drum assembly F is provided with a series of external ratchet teeth 5'1. extending around the circumference thereof and adapted to be engaged by a pawl 58 pivotally su ported on a bolt 58 fixed to a member 6i welded to the trolley frame. As shown, the pawl 58 is urged in a direction to engage the ratchet teeth 5'? upon rotation of the brake drum assembly F in a counterclockwise direction asviewed in Fig. 4 by a split friction ring 62 rotatenlarged portion of the member. Each of the slots 85 is [provided with thrust links 86, the outer ends of which engage within apertures 8'! in memb rs 88 welded to the brake shoes 38. The thrust links 86 are elongated, as clearly shown in Fig. 5, and the ends thereof are cylindrical as are the bottoms of the apertures 85- and 81. The slots 85 are slightly wider than the thrust links 86, see Fig. 3, which permits a slight pivotal movement of the links 86 in the slots. 85. The construction of the apertures 81 are also such that the thrust links 85 are free to pivot in the members 88. The direction of inclination of the links 86 is such that as the sleeve-like member 45 tends to rotate under the force of a load carried by the cable Hi the links 86 expand or force the brake shoes 38 into engagement with the brake drum assembly F, which assembly is held against rotation by the pawl 58, thus holding the load at any position regardless of power or any other like failure.

When it is desired to raise the load, the hoist motor I5 is caused to operate in a direction to rotate the shaft l8 in a clockwise direction as viewed in Fig. 3. Rotation of the shaft l8 drives been raised by the engagement of the pawl 58 drum assembly is now held against rotation by the pawl 58,.the brake shoes 38 drag against or slip along the inside of the brake drum assembly. The work of the motor I5 is only that required to'overcome the frictional resistance of the brake shoes. The links 85 and, in turn, the member 45 tend to follow the movement of the brake shoe assembly but cannot rotate unless the brake shoe assembly is rotated and under no circumstances can the member 45 rotate faster than or more than the brake shoe assembly. If the load tends to turn the driven member 45 faster than the brake shoe assembly or the shaft 18 the thrust links 86 alpply greater force on the brake shoes 38, thus automatically holding the load. Immediately upon cessation of the rotation of the shaft 18, the member 45 through the medium of the links 86 forces the brake shoes 38 into tight engagement with the brake drum assembly, thus preventing further rotation of the driven member 45.

The major portion of the energy involved in lowering the load is dissipated in the form of heat from the brake drum assembly, the circumference of which is provided with a plurality of heat radiating vanes or fins 90. A plurality of holes 9| in opposite ends of the brake drum assembly also facilitate dissipation of the heat generated. One of the principal advantages of. the present construction is the fact that due to the cylindrical form of the cooperating braking surfaces of the brake shoes and the brake drum assembly, a large braking area is effected at maximum distance from the center of rotation of the respective (parts while maintaining a minimum overall diameter. Another advantage of this construction is the location of the heat generating surfaces adjacent to the outside of the assembly, which construction facilitates quick dissipation of the heat generated through the vanes or fins 90. The construction of the brake is such that it operates satisfactorily through the life of the braking surface without adjustment; in other words, it is self-adjusting. This is of considerable advantage because there is no danger of the brake getting out of adiustment or being improperly adjusted by the hoist operator or the like.

From the foregoing description, it will be apparent that the objects heretofore enumerated and others have been accomplished and that there has been provided a new and improved air cooled load brake particularly adapted for use on overhead movable cranes and the like. While the preferred embodiment of the invention has been described in considerable detail, I do not wish to be limited to the preferred construction shown; which construction is merely illustrative of the invention and may be varied within the scope thereof and it is my intention to hereby cover all adaptations, modifications and uses thereof which come within the practice of those skilled in the art to which the invention relates and the spirit and scope of the appended claims.

Having thus described my invention, what I claim is:

1. In a load brake 'of the character referred to, the combination of a support. a rotatable drive member, a brake shoe operatively connected to said drive member and movable radially of the axis of rotation of said drive member, a brake member supported for rotation about an axis coaxial with the axis of rotation of said drive member and having an internal cylindrical surface adapted to be engaged by said brake shoe, a one-way automatic brake operatively connected to said brake member and to said support, a driven member supported for rotation about an-axis coaxial with said axis of rotation of said drive member and adapted to be connected to a load, and a driving connection between said brake shoe and said driven member for transmitting a force from one to the other so constructed and arranged that the transmitted force has a radial component acting upon said brake shoe.

2. In a load brake of the character referred to, the combination of a frame, a drive member adapted to be rotated in opposite directions, a brake shoe operatively connected to said drive member and movable radially of the axis of rotation of said drive member, an air-cooled brake drum member supported for rotation about an axis coaxial with the axis of rotation of said drive member, said brake drum member having an internal cylindrical surface adapted to be engaged by said brake shoe and said brake shoe having heat insulating brake lining on its engaging surface, a one-way automatic brake op eratively connected to said brake drum member and to said frame, a driven member supported for rotation about an axis coaxial with the axis of rotation of said drive member and adapted to be connected to a load, and a driving connection including a member interposed between and pivotally connected with said brake shoe and said driven member for transmitting a force therebetween and so constructed and arranged that the transmitted force has a radial component acting upon said brake shoe,

3. In a load brake of the character referred to, the combination of a support, a drive member adapted to be rotated in opposite directions, a brake shoe assembly, said brake shoe assembly comprising a carrier member fixed to said drive member and a brake shoe carried by said member and movable radially of the axis of rotation of said drive member, a brake member supported for rotation about an axis coaxial with the axis of rotation of said drive member and having an internal cylindrical surface adapted to be engaged by said brake shoe, a one-way automatic brake operatively connected to said brake member and to said support, a driven member supported for rotation about an axis coaxial with said axis of rotation of said drive member and adapted to be connected to a load, said driven member having a tangential portion thereof extending within said brake shoe assembly, and means including a member interposed between and pivotally connected to said brake shoe and said driven member for transmitting a force from one to the other and so constructed and arranged that the transmitted force has a radial component acting upon saidbrake shoe.

4. In a load brake of the character referred to, the combination of a frame, a drive member adapted to be rotated in opposite directions, a brake shoe assembly comprising a member fixed to said drive shaft and a brake shoe carried by said member and movable radially of the axis of rotation of said drive member, an air-cooled brake drum member supported for rotation about 72 arr-axis; coaxial; withthe axis of rotation of said: drive member, said brake drum member having an internal cylindrical surface adapted to be engaged by said brake shoe and said brake shoe havingheatiinsulating brake lining on itsengaging surface, a one-way automatic brake in the form of a. pawl and ratchet mechanism opera tively connected to said'brake drum member and to saidframe, a driven. member supported for rotation aboutan axis'coaxial with the axis of rotationof said drive member and adapted to be adapted to be rotated in opposite directions, a

brake shoe pivotally'connected to said drive memher for movement about an axis parallel with but oiTset from the axis of rotation of said drive member, a brake drum member supported for rotation about an axis coaxial with the axis of rotation of said drive member, said brake drum member having an internal cylindrical surface adapted to be engaged by said brake shoe, a oneway automatic brake operatively connected to said brake drum member and to said frame, a driven member supported for rotation about an axis coaxial with said axis of rotation of said drive member, and a driving connection between said brake shoe and said driven member for transmitting a force from one to the other so constructedand arranged that thetransmitted force has a radial component acting upon said brake shoe.

6. In a load brake of the character referred to, the combination of a frame, a rotatable drive member adapted to be rotated in opposite directions, a brake shoe pivotally connected to said sulating brake liningon its engaging surface, a

one-way automatic brake operatively connected .to said brake drum member and to said frame, a

driven member supported for rotation aboutan axis coaxial with said axis of rotation of said drive member, and means pivotally connected to said brake shoe and to said driven member for transmitting a force from one to the other so constructed and arranged that the transmitted force has a radial component acting upon said brake shoe.

7. ;In'a load brake-of the character referred to, the combination of a frame,- a drive member adapted to be rotated in opposite directions, a brake shoe carrier member fixedly secured to said drive member, a brake shoe pivotally connected to said brake shoe carrier member for movement radially of the axis of rotation of said drive member, a brake drum member supported for rotation about an axis'coaxial with the axis of rotation of said drivermember, said brake drum member havdriven member having apertures thereinv open ing into-adjacent sides thereof, 'andithrust members engaging in saidgapertures' for connecting: said brake shoe and said drivenmemberwhereby said brake shoe is movedlradially outwardly bya; load applied tosaid-drivenmember.

8. In aloadbrakeofthecharacter referred to, the combination of a. frame, a rotatableldrivei memberadapted to -be rotated: in oppositedirec'tions, a brake'shoeassembly comprising a member fixedly *secured'ito said drivemember and a brake shoe pivotally. connectedzto said member for movement radially-of the axis of rotation of said drive member; a brake-drum membersupported. for rotation; about 311' axis coaxial with the axis of rotation of. said drive member, said.-

brake drum member having an "internalcylindrie cal surface adapted to be engaged bysaidkbrake shoe and said brake shoe having a heat resist.- ing brake lining on its engaging surface;- a onewayautomatic: brake" op'eratively connected to said brakedrum member and to said frame, a

driven member supported for'arotation'about an;

axis coaxial withsaid axis offrotatiorr of said drive member. and adapted. to be connected to a load, said driven member:havingatportion thliei-i of extending within said brake shoe assembly; said brake shoe and said driven member'hav ing apertures therein opening into adjoiningsides, and rigid: thrust members interposedibe tween said brake shoe and said driven member and engaging within said aperturesfor connecting the same whereby said brake shoe is moved radially by a load applied to said. driven member;

9. In a load'brake oftlie character referred to,

the combination of a frame, a drive member adapted to be rotated"i n opposite directions," a brake shoe carrier member fixedly secured to said" drive member, a brake shoe carried by saidbraka sho'e carrier member andi'movable radially. ofthe' axis of rotation ofsaid drive member, a brake drum member supported for rotation about-an axis coaxial with the axis of rotation of said drive member, said brake drum member'having' an internal cylindrical surface adapted to be engaged by said brake sh'oe,a one-way? automatic brake operatively connected to said brake drum member and to said frame, a driven member sup-. ported for rotation about an axis coaxial with said axis of rotation of said drive member and extending into said'brake shoe carrier member, said driven member being adapted to have a load applied thereto tending to rotate the same in a given direction, and means interposed be.- tween'and pivotally connected with said brake shoe'and said driven memberfor transmitting a force from one to. the other so oonstructed'and arranged that the transmitted force has a radial component acting upon saidbrake shoes 10. In a load brake'of the character'referred to, the combination of a frame, ,a-rotatable drive member adapted to be rotated in oppositedirections, a brake shoe pivotally connected to said drive member and movable radially of the axis of rotationthereof, an air-cooled brake. drum member supportedgfor; rotation-a aboutzan axiscoaxial with the axis of rotation of said drive member, said brake drum member having an internal cylindrical surface adapted to be engaged by said brake shoe and said brake shoe having a heat insulating lining on the face thereof, a oneway automatic brake operatively connected to said brake drum member and to said frame, a driven member supported for rotation about an axis coaxial with said axis of rotation of said drive member, said driven member being adapted to have a load applied thereto tending to rotate the same in a given direction, and thrust members interposed between and pivotally connected with said brake shoe and said driven member whereby a load operatively connected to said driven member exerts a force on said brake shoe tending to move the same in a radially outward direction.

11. In a load brake of the character referred to, the combination of a frame, a rotatable drive member adapted to be rotated in opposite directions, a brake shoe assembly comprising a carrier member fixedly secured to said drive member and a plurality of brake shoes pivotally connected to said carrier member and movable radially of the axis of rotation of said drive member, an air-cooled brake drum member supported for rotation about an axis coaxial with the axis of rotation of said drive member, said brake drum member having an internal cylindrical surface adapted to be engaged by said brake shoes and said brake shoes having heat insulating linings connected to the engaging surfaces thereof, a one-way automatic brake operatively connected to said brake drum member and to said frame, a driven member supported for rotation about an axis coaxial with said axis of rotation of said drive member and extending into said brake shoe assembly, said driven member being adapted to have a load connected thereto tending to rotate the same in a given direction, and rigid thrust members interposed between and. pivotally connected with said brake shoes and said driven member whereby a load operatively connected to said driven member urges said brake shoe radially outwardly.

12. In a load brake of the character referred to, the combination of a brake, a drive member adapted to be rotated in opposite directions, a brake shoe assembly comprising a carrier member fixedly secured to said drive member and a plurality of brake shoes pivotally connected to said carrier for movement about axes parallel with but offset from the axis of rotation of said drive member, an air-cooled brake drum member supported for rotation about an axis coaxial With the axis of rotation of said drive member, said brake drum member having an internal cylindrical surface adapted to be engaged by said brake shoes and said brake shoes having heat insulating brake lining on its engaging surfaces, a plurality of heat radiating fins on the exterior of said brake drum member, a one-way automatic brake in the form of a pawl and ratchet mechanism operatively connected to said brake drum member and to said frame, a driven member rotatably supported on said drive member and having a portion thereof extending into said brake shoe assembly, said driven member being adapted to be connected to a load tending to rotate the same in a given direction, and a rigid thrust link interposed between said brake shoe and said driven member whereby a load applied to said driven 10 member exerts a force on said brake shoes in a radially outward direction.

13. In a brake of the character referred to, the combination of a support, a first rotatable member, a second rotatable member supported coaxially with said first rotatable member, one of said rotatable members being adapted to be operatively connected to a drive means and the other to a load, a brake shoe operatively connected to said first rotatable member for rotation therewith and movement radially of the axis of rotation thereof, a brake member supported for rotation about an axis coaxial with the axis of rotation of said members and having an internal cylindrical surface adapted to be engaged by said brake shoe, a one-way automatic brake operatively connected to said brake member and to said support for permitting rotation thereof only in the direction to raise a load, and a tangential driving connection between said brake shoe and said second rotatable member for trans mitting a force from one of said rotatable members to the other.

14. In a brake of the character referred to, the combination of a support, a first rotatable member, a second rotatable member supported coaxially with said first rotatable member, one of said rotatable members being adapted to be operatively connected to a drive means and the other to a load, a brake shoe operatively connected to said first rotatable member for rotation therewith and movement radially of the axis of rotation thereof, a generally cylindrical brake member supported for rotation about an axis coaxial with the axis of rotation of said members and having radially projecting fins on the exterior thereof, an internal cylindrical surface adapted to be engaged by said brake shoe, 9. oneway automatic brake operatively connected to said brake member and to said support for permitting rotation thereof only in the direction to raise a load, and a driving connection between said brake shoe and said second rotatable member for transmitting a force from one of said rotatable members to the other so constructed and arranged that the transmitted force has a radial component acting upon said brake shoe.

WILLIAM G. WEI-IR.

REFERENCES CITED The following references are of record in the file of this patent:

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